What is a carrier?

The body’s immune system doesn’t always completely eliminate HBV: 5 per cent of infected adults still carry the virus in their blood six months after they first became ill, even though all symptoms have cleared up. These people are called hepatitis В carriers, and can pass on the infection to others.

Half of them will get rid of the virus and become non-infectious over the next two years. The rest remain infected (and infectious) and are at risk of developing complications such as chronic liver disease, cirrhosis and cancer of the liver later in life. A person may become a carrier without having developed symptoms after becoming infected.

How common is hepatitis B?

It is estimated that, worldwide, there are around 300 million carriers of HBV. It is mainly the carriers, especially those who don’t know they’ve ever been infected, who keep spreading hepatitis B. The number of people infected by HBV varies in different parts of the world. The prevalence of hepatitis В also varies between different population groups within a country. In Australia, chronic carriers of the infection are most commonly found among homosexual men, intravenous drug users, Aborigines and migrants from Southeast Asia.

How is hepatitis В diagnosed?

Present and past infection and the carrier state can be diagnosed by a simple blood test that may be performed on request by any doctor, public hospital or sexual health clinic for anyone who thinks they may have ever been at risk.

If you develop jaundice and the other typical symptoms of hepatitis, you will be offered a test for hepatitis В along with other blood tests to try to find the cause of the symptoms and to see how much your liver function has been disturbed. You’ll be advised to have further blood tests after the jaundice has faded and until liver function is normal again, and, if your hepatitis is caused by HBV, to see whether you’ve become immune or a carrier.

The blood tests are very reliable. The diagnosis is only likely to be missed if hepatitis В causes mild symptoms or none.
How can hepatitis В be prevented? Spread can be prevented by avoiding contact with body fluids of infected persons or carriers, particularly blood and sexual secretions. Good hygiene and staying with one sexual partner make wise precautions.
Sexual and other close contacts of people with hepatitis В should ask their doctor whether they need a vaccination for post-exposure or for permanent immunity.

If babies are exposed to HBV at birth, treatment can be given to help prevent them from becoming carriers.

Hepatitis В vaccination

Vaccination to give permanent immunity against hepatitis В is now available: three injections, two a month apart and the third six months later. It is advisable for all sexual and close contacts of carriers and for sex workers, health workers and others at risk of contact with other people’s body fluids.